1
Pharyngeal arches and Pharyngeal arches and pouchespouches
L.MossL.Moss--SalentijnSalentijn
Pharyngeal arches: a definitionPharyngeal arches: a definitionA A segmentalsegmental seriesseries of five paired swellings that surround of five paired swellings that surround the foregut between days 20 to 35 of embryonic the foregut between days 20 to 35 of embryonic development. These segments, which are unique to development. These segments, which are unique to vertebrates and their immediate precursors, are “wedged” vertebrates and their immediate precursors, are “wedged” between the developing forebrain and heart.between the developing forebrain and heart.
Pharyngeal archesPharyngeal arches
a.k.a. visceral or branchial archesa.k.a. visceral or branchial archesDevelop (and disappear as distinctively visible Develop (and disappear as distinctively visible structures) in a rostrostructures) in a rostro--caudal sequencecaudal sequenceRequire neural crest cells for their developmentRequire neural crest cells for their developmentEven after they are no longer visible externally, Even after they are no longer visible externally, they have a lasting impact on the anatomy of the they have a lasting impact on the anatomy of the head and neck and of the great vesselshead and neck and of the great vessels
Basic body plan of all chordates Basic body plan of all chordates (incl. vertebrates)(incl. vertebrates)
Dorsal hollow neural tubeDorsal hollow neural tube
Segmented lateral mesodermSegmented lateral mesodermSegmented lateral mesodermSegmented lateral mesoderm
Central notochordCentral notochord
Ventral digestive tubeVentral digestive tube
(Pharyngeal gill slits)(Pharyngeal gill slits)
photograph by Purcell R,National Geographic November 2006
Dell H (2006)
(Gill slits)
(Pharyngeal arches)
2
5 Pharyngeal arches 5 Pharyngeal arches
5 Aortic arches 5 Aortic arches
Arches numbered 1Arches numbered 1--66
Netter F, Ciba collection
Arches, grooves, pouches, and Arches, grooves, pouches, and membranesmembranes
Pharyngeal groovePharyngeal groovePharyngeal groovePharyngeal groove
Pharyngeal archPharyngeal arch
Pharyngeal Pharyngeal membranemembrane
Pharyngeal pouchPharyngeal pouch
ForegutForegut
Pharyngeal cleftPharyngeal clefttransient “gilltransient “gill--slit” slit”
Mangold U et al (1981)
Mesenchyme in cephalic region Mesenchyme in cephalic region is derived from:is derived from:
MesodermMesodermMesodermMesodermNeural crestNeural crest
Chai Y, Ito Y, Han J (2003) Graham A et al (2003)
3
Noden DM, Schneider RA (2006)
Noden DM, Schneider RA (2006)
Extent of cephalic (cranial) Extent of cephalic (cranial) neural crestneural crest
Phillips MT, Kirby ML et al, (1987)
Neural crest involvement in the Neural crest involvement in the development of the heartdevelopment of the heart
Kuratani S, Horigome N (2000)
Kirby ML, Waldo KL (1990)
Kuratani, Shigeru (1997) Iimura T, Pourquié O (2007)
4
Larsen WJ (2001)
Wurdak H et al (2006)
Segmental Segmental components components of archesof arches
Connective tissues Connective tissues -- ncnc
Ten Cate AR (1988)
Artery Artery –– mesodermmesoderm--first to appearfirst to appear
Skeletal barSkeletal bar-- nc nc --(cartilage) last to form(cartilage) last to form
Branchiomeric nerve Branchiomeric nerve ––nc,ectoderm,neurectodermnc,ectoderm,neurectoderm
Muscle Muscle –– mesodermmesoderm
5 Aortic arches 5 Aortic arches
Arches numbered 1Arches numbered 1--66
Netter F, Ciba collection
Aortic arch developmentAortic arch developmentHiruma T, Hirakow R (1995)
Aortic arch Aortic arch developmentdevelopmentdevelopment development cont’dcont’d
Hiruma T, Hirakow R (1995)
5
Muscles
Arch 1: Muscles of mastication (V)Arch 1: Muscles of mastication (V)Arch 2: Muscles of facial expression (VII)Arch 2: Muscles of facial expression (VII)Arch 3: Stylopharyngeus muscle (IX)Arch 3: Stylopharyngeus muscle (IX)Arch 4Arch 4--6: Laryngeal muscles (X6: Laryngeal muscles (X--XI)XI) Noden D M, Lahunta A de (1985)
The cartilage The cartilage elements of the elements of the pharyngeal pharyngeal arches arches (cartilaginous (cartilaginous i ii i
Arey’s Embryology
viscerocranium, viscerocranium, purple)purple) at 7 at 7 weeks. weeks.
Skeletal Skeletal elementselements
Moss-Salentijn L et al (1972)Moss-Salentijn L et al (1972)
Skeletal Skeletal derivativesderivatives
Larsen WJ (2001)
External ear receives External ear receives contributions from arches 1 and 2contributions from arches 1 and 2
Netter F, Ciba collection
6
External ear development by External ear development by merging of 6 auricular hillocksmerging of 6 auricular hillocks
Tuchmann-Duplessis H et al, (1975)
Endodermal swellings on arches Endodermal swellings on arches 11--4 contribute to the tongue4 contribute to the tongue
1. Paired lingual swellings and 1. Paired lingual swellings and single median tuberculum imparsingle median tuberculum impar
2. Single median copula2. Single median copulag pg p
33--4. Combined median hypobranchial 4. Combined median hypobranchial eminence eminence
Ten Cate AR (1988)
Merging Merging of lingual of lingual swellingsswellingsswellingsswellings
Ten Cate AR (1988)
Fate of pharyngeal grooves 2Fate of pharyngeal grooves 2--44
Covered by rapid Covered by rapid h f 2h f 2 ddoutgrowth of 2outgrowth of 2ndnd
arch “operculum.”arch “operculum.”
Tuchmann-Duplessis H, Haegel P (1975)
Netter F, Ciba collection
Endoderm plays key role in Endoderm plays key role in morphogenesis of pharyngeal regionmorphogenesis of pharyngeal region
Graham A et al (2004)Pax-1
BMP-7
Fgf-8
7
Derivatives of dorsal and ventral Derivatives of dorsal and ventral parts of pharyngeal pouchesparts of pharyngeal pouches
Brookes M, Zietman A (1998)
Tuchmann-Duplessis H, Haegel P (1975)
Thyroid gland development Thyroid gland development Thyroglossal duct Thyroglossal duct
Watt, Marie A, and Sanders, ColinUniversity of Glasgow
Superior and Superior and inferior inferior
parathyroid parathyroid l dl dglandsglands
Tuchmann-Duplessis H, Haegel P (1975)Larsen WJ (2001)